To establish a method for the determination of folic acid in fortified foods by high performance liquid chromatography (HPLC) with post-column photochemical derivatization.MethodsChromatographic separation was carried out using a SunFire C₁₈ column (4.6 mm× 250 mm, 5 μm). The mobile phases was acetonitrile and 50 mmol/L potassium dihydrogen phosphate solution (pH=5.0) with an optimized gradient elution. Post-column photochemical derivatization of folic acid was under UV-light irradiation at 254 nm. The fluorescence detection was performed with the excitation at 344 nm and the emission at 428 nm. ResultsThe linear range was 0.01-2.0 μg/ml, r=0.999 9. The limit of detection (LOD) was 0.01 μg/g and the limit of quantification (LOQ) was 0.03 μg/g. The average recoveries were 90.0%-98.0% and the RSD of the method was less than 5%.ConclusionThe method was simple, rapid, accurate, reproducible, and suitable for the determination of folic acid in fortified foods.